Abstract
A hydroxycoumarin glucoside, aesculin, is found in the bark of Aesculus hippocastanum L. cultivated in Europe. The present workers proved the presence of fraxetin, instead. of aesculin or aesculetin, in the bark of Aesculus turbinata Bl. growing wild in Japan (This Journal: 57, 618 (1937)). This compound might exist as its glucoside in the living plant but the confirmation of such was not made in the previous experiments. In the present series of experiments, however, fraxin was proved as a glucoside. The raw material was directly extracted with an organic solvent or extracted with water and obtained by the lead precipitation method. Fraxin thus obtained showed the m.p. of 209-210° by the former method and m.p. 200° by the latter, both being identical in properties and coloration as given in literatures. Methylation of fraxin followed by hydrolysis yielded 7-monomethylfraxetin, m.p. 195°, and its acetylation, 7-methyl-8-acetylfraxetin, m.p. 147.5-148°.
